Such a device has been known, e.g., from EP 0 829 227 A2. The pneumatic pressure in a cuff around an extremity of a patient is determined by means of such a device with a pressure gauge and subsequently evaluated. Important requirements imposed on such devices for practice include flexible handling, robustness and measurements not affected by external disturbances. External disturbances usually originate from mechanical effects on the pneumatic system of the measuring device, which comprises, in general, the elements cuff, pressure sensor, pump, valve, and pneumatic connection lines.
Mechanical effects on the pneumatic system, especially on the flexible pneumatic connection lines, are due, in particular, to movements of the patient and cause disturbing signals. However, these signals are not physiological and therefore lead to incorrect measurement results or even to an interruption of the measurement. It has therefore been suggested that such disturbances be compensated by numerical processes, but such processes are complicated and have ultimately no effect on the mechanical causes proper of the disturbances.